APA aipamena

 Babbie, E. (1990).  Survey research methords.  Wadsworth Pub. Co.

Chicago Style aipamena

 Babbie, Earl.  Survey Research Methords.  Wadsworth Pub. Co, 1990.

MLA aipamena

 Babbie, Earl.  Survey Research Methords.  Wadsworth Pub. Co, 1990.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.